Transport and Transformation of Urea and Its Derivatives through a Mineral Subsoil

摘要: The transport and transformation potential of N compounds derived from urea, applied as a deicing agent during the winter period, have been investigated in coarse, heterogeneous glacial-contact deposit southeast Norway. hydrolysis urea to ammonium-N (NH 4 + -N) subsequent oxidation nitrate-N (NO 3 - was monitored by extraction soil water five depths (from 70 220 cm) lysimeter trench. Urea through profile is normally negligible, although hydrophilic, uncharged molecule. In this study, rapidly transported at least cm. measured urea-N concentrations varied 2 50 mg L -1 throughout profile. This explained minimal hydrolytic activity because temperatures close 0°C, different preferential flow mechanisms being important snowmelt period. occurred all depths. NH -N formed situ oxidized NO -N. nitrification started immediately most rapid 70- 105-cm depth, but detectable down cm 120 d after solute application. Nitrification also following One year application, about 40% recovered unsaturated zone (0-450 cm), it estimated that 50% will reach groundwater